// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
// Copyright (C) 2008 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_IO_H
#define EIGEN_IO_H

namespace Eigen {

enum
{
	DontAlignCols = 1
};
enum
{
	StreamPrecision = -1,
	FullPrecision = -2
};

namespace internal {
template<typename Derived>
std::ostream&
print_matrix(std::ostream& s, const Derived& _m, const IOFormat& fmt);
}

/** \class IOFormat
 * \ingroup Core_Module
 *
 * \brief Stores a set of parameters controlling the way matrices are printed
 *
 * List of available parameters:
 *  - \b precision number of digits for floating point values, or one of the special constants \c StreamPrecision and \c
 * FullPrecision. The default is the special value \c StreamPrecision which means to use the stream's own precision
 * setting, as set for instance using \c cout.precision(3). The other special value \c FullPrecision means that the
 * number of digits will be computed to match the full precision of each floating-point type.
 *  - \b flags an OR-ed combination of flags, the default value is 0, the only currently available flag is \c
 * DontAlignCols which allows to disable the alignment of columns, resulting in faster code.
 *  - \b coeffSeparator string printed between two coefficients of the same row
 *  - \b rowSeparator string printed between two rows
 *  - \b rowPrefix string printed at the beginning of each row
 *  - \b rowSuffix string printed at the end of each row
 *  - \b matPrefix string printed at the beginning of the matrix
 *  - \b matSuffix string printed at the end of the matrix
 *  - \b fill character printed to fill the empty space in aligned columns
 *
 * Example: \include IOFormat.cpp
 * Output: \verbinclude IOFormat.out
 *
 * \sa DenseBase::format(), class WithFormat
 */
struct IOFormat
{
	/** Default constructor, see class IOFormat for the meaning of the parameters */
	IOFormat(int _precision = StreamPrecision,
			 int _flags = 0,
			 const std::string& _coeffSeparator = " ",
			 const std::string& _rowSeparator = "\n",
			 const std::string& _rowPrefix = "",
			 const std::string& _rowSuffix = "",
			 const std::string& _matPrefix = "",
			 const std::string& _matSuffix = "",
			 const char _fill = ' ')
		: matPrefix(_matPrefix)
		, matSuffix(_matSuffix)
		, rowPrefix(_rowPrefix)
		, rowSuffix(_rowSuffix)
		, rowSeparator(_rowSeparator)
		, rowSpacer("")
		, coeffSeparator(_coeffSeparator)
		, fill(_fill)
		, precision(_precision)
		, flags(_flags)
	{
		// TODO check if rowPrefix, rowSuffix or rowSeparator contains a newline
		// don't add rowSpacer if columns are not to be aligned
		if ((flags & DontAlignCols))
			return;
		int i = int(matSuffix.length()) - 1;
		while (i >= 0 && matSuffix[i] != '\n') {
			rowSpacer += ' ';
			i--;
		}
	}
	std::string matPrefix, matSuffix;
	std::string rowPrefix, rowSuffix, rowSeparator, rowSpacer;
	std::string coeffSeparator;
	char fill;
	int precision;
	int flags;
};

/** \class WithFormat
 * \ingroup Core_Module
 *
 * \brief Pseudo expression providing matrix output with given format
 *
 * \tparam ExpressionType the type of the object on which IO stream operations are performed
 *
 * This class represents an expression with stream operators controlled by a given IOFormat.
 * It is the return type of DenseBase::format()
 * and most of the time this is the only way it is used.
 *
 * See class IOFormat for some examples.
 *
 * \sa DenseBase::format(), class IOFormat
 */
template<typename ExpressionType>
class WithFormat
{
  public:
	WithFormat(const ExpressionType& matrix, const IOFormat& format)
		: m_matrix(matrix)
		, m_format(format)
	{
	}

	friend std::ostream& operator<<(std::ostream& s, const WithFormat& wf)
	{
		return internal::print_matrix(s, wf.m_matrix.eval(), wf.m_format);
	}

  protected:
	typename ExpressionType::Nested m_matrix;
	IOFormat m_format;
};

namespace internal {

// NOTE: This helper is kept for backward compatibility with previous code specializing
//       this internal::significant_decimals_impl structure. In the future we should directly
//       call digits10() which has been introduced in July 2016 in 3.3.
template<typename Scalar>
struct significant_decimals_impl
{
	static inline int run() { return NumTraits<Scalar>::digits10(); }
};

/** \internal
 * print the matrix \a _m to the output stream \a s using the output format \a fmt */
template<typename Derived>
std::ostream&
print_matrix(std::ostream& s, const Derived& _m, const IOFormat& fmt)
{
	using internal::conditional;
	using internal::is_same;

	if (_m.size() == 0) {
		s << fmt.matPrefix << fmt.matSuffix;
		return s;
	}

	typename Derived::Nested m = _m;
	typedef typename Derived::Scalar Scalar;
	typedef typename conditional<is_same<Scalar, char>::value || is_same<Scalar, unsigned char>::value ||
									 is_same<Scalar, numext::int8_t>::value || is_same<Scalar, numext::uint8_t>::value,
								 int,
								 typename conditional<is_same<Scalar, std::complex<char>>::value ||
														  is_same<Scalar, std::complex<unsigned char>>::value ||
														  is_same<Scalar, std::complex<numext::int8_t>>::value ||
														  is_same<Scalar, std::complex<numext::uint8_t>>::value,
													  std::complex<int>,
													  const Scalar&>::type>::type PrintType;

	Index width = 0;

	std::streamsize explicit_precision;
	if (fmt.precision == StreamPrecision) {
		explicit_precision = 0;
	} else if (fmt.precision == FullPrecision) {
		if (NumTraits<Scalar>::IsInteger) {
			explicit_precision = 0;
		} else {
			explicit_precision = significant_decimals_impl<Scalar>::run();
		}
	} else {
		explicit_precision = fmt.precision;
	}

	std::streamsize old_precision = 0;
	if (explicit_precision)
		old_precision = s.precision(explicit_precision);

	bool align_cols = !(fmt.flags & DontAlignCols);
	if (align_cols) {
		// compute the largest width
		for (Index j = 0; j < m.cols(); ++j)
			for (Index i = 0; i < m.rows(); ++i) {
				std::stringstream sstr;
				sstr.copyfmt(s);
				sstr << static_cast<PrintType>(m.coeff(i, j));
				width = std::max<Index>(width, Index(sstr.str().length()));
			}
	}
	std::streamsize old_width = s.width();
	char old_fill_character = s.fill();
	s << fmt.matPrefix;
	for (Index i = 0; i < m.rows(); ++i) {
		if (i)
			s << fmt.rowSpacer;
		s << fmt.rowPrefix;
		if (width) {
			s.fill(fmt.fill);
			s.width(width);
		}
		s << static_cast<PrintType>(m.coeff(i, 0));
		for (Index j = 1; j < m.cols(); ++j) {
			s << fmt.coeffSeparator;
			if (width) {
				s.fill(fmt.fill);
				s.width(width);
			}
			s << static_cast<PrintType>(m.coeff(i, j));
		}
		s << fmt.rowSuffix;
		if (i < m.rows() - 1)
			s << fmt.rowSeparator;
	}
	s << fmt.matSuffix;
	if (explicit_precision)
		s.precision(old_precision);
	if (width) {
		s.fill(old_fill_character);
		s.width(old_width);
	}
	return s;
}

} // end namespace internal

/** \relates DenseBase
 *
 * Outputs the matrix, to the given stream.
 *
 * If you wish to print the matrix with a format different than the default, use DenseBase::format().
 *
 * It is also possible to change the default format by defining EIGEN_DEFAULT_IO_FORMAT before including Eigen headers.
 * If not defined, this will automatically be defined to Eigen::IOFormat(), that is the Eigen::IOFormat with default
 * parameters.
 *
 * \sa DenseBase::format()
 */
template<typename Derived>
std::ostream&
operator<<(std::ostream& s, const DenseBase<Derived>& m)
{
	return internal::print_matrix(s, m.eval(), EIGEN_DEFAULT_IO_FORMAT);
}

} // end namespace Eigen

#endif // EIGEN_IO_H
